Big Bore Calibers

OK what is exactly the lowest of what is considered big bore,35' 40 handgun and rifle and what about millimeters just something that nobody can agree on.I think everybody has their own opinion on big bore calibers.Just like with the bolt action what is long action and what is short action?

Just my opinion. My opinion and $1.55 will get you a medium coffee at Tim Horton's.
Big Bore Handguns are 40 cal. and above.
Big Bore rifles are 44 cal. and above.
As for Bolt Guns, I agree with the industry standard.
Ex; 30-06 is a long action and 308 is a short action.

I'm pretty much lined up with Greyhawk on this except for the rifles. I think big bore rifles start at 40cal. Back in the day the .40-65, .40-82 and the .405 were considered 'big medicine'. TR made a name for himself as a big game hunter using the .405Win. I think today many African nations draw the line between medium and big bore right between the 375 and the 40cal. I think most of us would agree with that logic if we fired a box of .416 Rem Mag from the bench.